DTC Troubleshooting: U0122 (184)
DTC U0122:
 F-CAN Malfunction (ECM-VSA Modulator-Control Unit)
NOTE: Before you troubleshoot, record all freeze data and review the general troubleshooting information.
  1. Turn the ignition switch ON (II).
  1. Check for Temporary DTCs or DTCs in the DTCs MENU with the HDS.
Are DTC U0028 and U0122 indicated at the same time?
YES -
NO -
Go to Step 3 .
  1. Clear the DTC with the HDS.
  1. Check for Temporary DTCs or DTCs in the DTCs MENU with the HDS.
Is DTC U0122 indicated?
YES -
Go to Step 5 .
NO -
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the gauge control module (tach), the VSA modulator-control unit, and the ECM.■
  1. Check for communication to the VSA system.
Does the HDS communicate with the VSA system?
YES -
Go to Step 6 .
NO -
  1. Turn the ignition switch OFF, and wait 2 minutes.
  1. Disconnect the VSA modulator-control unit 46P connector.
  1. Disconnect ECM connector No. 2 (58P).
  1. Connect ECM connector No. 2 terminal No. 47 to body ground with a jumper wire.
  1. Check for continuity between VSA modulator-control unit 46P connector terminal No. 39 and body ground.
Is there continuity?
YES -
Go to Step 11 .
NO -
Repair open in the wire between the VSA modulator-control unit and ECM connector No. 2 terminal No. 47, then go to Step 13 .
  1. Connect ECM connector No. 2 terminal No. 48 to body ground with a jumper wire.
  1. Check for continuity between VSA modulator-control unit 46P connector terminal No. 38 and body ground.
Is there continuity?
YES -
NO -
Repair open in the wire between the VSA modulator-control unit and ECM connector No. 2 terminal No. 48, then go to Step 13 .
  1. Reconnect all connectors.
  1. Turn the ignition switch ON (II).
  1. Reset the ECM with the HDS.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC U0122 indicated?
YES -
Check for poor connections or loose terminals at the gauge control module (tach), the VSA modulator-control unit, and the ECM, then go to Step 1 .
NO -
Troubleshooting is complete. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.■